Screwable bearing housing cover for a supercharging device

ABSTRACT

A bearing housing may have a bearing housing cover formed of metal. A first thread may be arranged on the bearing housing cover and a second thread may be arranged on the bearing housing and designed complementarily to the first thread so that the bearing housing cover may be screwed on and fixed on the bearing housing through a rotational movement.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application 10 2011075 517.9 filed on May 9, 2011, German Patent Application 20 2010 017275.6 filed on Jun. 29, 2010, and International Patent ApplicationPCT/EP2011/060794 filed on Jun. 28, 2011, all of which are herebyincorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a bearing housing cover for a bearinghousing of a charging device, in particular for an exhaust gasturbocharger of a motor vehicle. Furthermore, an exhaust gasturbocharger having such a bearing housing is likewise subject of theinvention.

BACKGROUND

From WO 2010/002717 A2 a generic bearing housing for an exhaust gasturbocharger is known. On the compressor side, the bearing housingcomprises an opening which is closed off with a bearing housing cover.Thus, through the bearing housing cover, the compressor housing interiorcan be divided from or closed off against the bearing housing interiorin a gas-tight manner. The bearing housing cover can be fixed to thebearing housing with a bayonet closure. The bearing housing cover isdesigned furthermore in such a manner that in installation position itserves as mounting for the shaft sealing rings or piston rings.

Usually, a bearing housing cover is currently embodied with acircumferential annular groove for a sealing element such as for examplean O-ring. Thus, the manufacture of the bearing housing cover requires aplurality of machining operations and among other things can only beaccomplished with elaborate design and in an expensive manner for thisreason.

SUMMARY

The present invention now deals with the problem of stating an improvedor at least an alternative embodiment for a bearing housing cover and abearing housing which is characterized in particular by a simpleassembly and a reduced parts variety.

According to the invention, this problem is solved through the subjectsof the independent claims. Advantageous embodiments are subject of thedependent claims.

In the case of a bearing housing of a charging device, the presentinvention is based on the general idea of fixing a bearing housing coverclosing off the bearing housing to the actual bearing housing via ascrew connection, wherein the bearing housing cover itself forms a screwelement. The term screw connection thus does not mean additional screwsvia which the bearing housing cover is securely screwed to the bearinghousing, but the bearing housing cover itself is designed as screw andcan be securely screwed and thus fixed to the bearing housing through arotational movement. To this end, the bearing housing cover according tothe invention comprises a first thread, whereas the bearing housingaccording to the invention comprises a second thread designedcomplementarily thereto, so that the bearing housing cover can bescrewed to the bearing housing through a simple rotational movement.Because of this, the omission of additional fastening means, such as forexample screws, is possible, likewise the omission of additional sealingmeans such as for example O-ring seals. Through the omission of theseadditional parts, the parts variety can be substantially reduced and theassembly additionally simplified.

With an advantageous further development of the solution according tothe invention, the first thread is an external thread and the secondthread an internal thread designed complementarily thereto, wherein theexternal thread can be additionally designed in a self-locking manner.With this embodiment, a simple screwing-in of the bearing housing coverinto the internal thread on the bearing housing is made possible,wherein for the simplified screwing-in for example a sliding agent canbe additionally and purely optionally used. In order to achieve as tightas possible an arrangement of the bearing housing cover on the bearinghousing, a seal can be provided on the face end of the bearing housingcover, in particular a seal sprayed on by means of a screen printingmethod, via which the bearing housing cover tightly bears against acorresponding bearing contour of the bearing housing. Through thissprayed-on and therefore easy-to-manufacture seal together with theself-locking external thread, a simple and at the same time reliablytight closure of the bearing housing through the bearing housing covercan be achieved.

With an advantageous further development of the solution according tothe invention, the bearing housing cover is produced by means of aforming method, in particular by means of forging or cold extrusion.Such extrusion methods usually belong to the pressure forming methods,with which the material to be formed is made to flow under the effect ofa high pressure. The forming usually takes place at room temperature,which in this case it is called cold extrusion. Components produced insuch a manner and in the present case bearing housing covers arecharacterized by a particularly high dimensional accuracy and a highsurface quality. A particular advantage hereby is that suchcold-extruded components can be produced particularly cost-effectivelyyet in a high quality. During forging, by contrast, the work piece to beproduced is pressure-formed between two dies without cutting, namelyusually above or below the re-crystallisation temperature, which is whythe words hot or cold forming are used. Advantages in particular are alow material loss in contrast with cutting machining and because of thisan economical manufacturability.

Practically, the bearing housing cover is designed of steel andcomprises a corrosion protection in the form of a nitrocarburizing or aburnishing. The nitrocarburizing is a gas nitriting connected withcarbon absorption, as a result of which surfaces are usually hardened.The burnishing, by contrast, serves for forming a protective layer offerrous surfaces in order to reduce the corrosion hazard by doing so.Both methods, i.e. both the nitrocarburizing as well as the burnishingsubstantially increase the corrosion resistance, by which in particularhigh-quality materials of steel can be finished.

Further important features and advantages of the invention are obtainedfrom the subclaims, from the drawings and from the associated Figuredescription by means of the drawings.

It is to be understood that the features mentioned above and still to beexplained in the following cannot only be used in the respectivecombination stated but also in other combinations or by themselveswithout leaving the scope of the present invention.

Preferred exemplary embodiment of the invention are shown in thedrawings and are explained in more detail in the following description,wherein same reference characters relate to same or similar orfunctionally same components.

BRIEF DESCRIPTION OF THE DRAWINGS

It shows, in each case schematically:

FIG. 1 a sectional representation through a bearing housing according tothe invention with a bearing housing cover screwed into said bearinghousing,

FIG. 2 a view of a possible embodiment of the bearing housing cover.

DETAILED DESCRIPTION

According to FIG. 1, a bearing housing 1 of a charging device which isnot otherwise shown, for example of an exhaust gas turbocharger of amotor vehicle, comprises a bearing housing cover 2 formed of metal. Inorder to fasten the bearing housing cover 2 to the bearing housing 1 ina preferably simple manner and because of this also seal in particularthe bearing housing 1 in axial direction, a first thread 3 is providedon the bearing housing cover 2 and a second thread 4 formedcomplementarily thereto is provided on the bearing housing 1 accordingto the invention, so that the bearing housing cover 2 can be screwed tothe bearing housing 1 through a simple rotational movement. The firstthread 3 on the bearing housing cover 2 in this case is designed asexternal thread, whereas the second thread 4 on the bearing housing 1 isconfigured as internal thread designed complementarily thereto, or viceversa. In addition, the external thread and/or the internal thread, i.e.the first thread 3 and/or the second thread 4 can be designed in aself-locking manner, as a result of which an unintentional loosening ofthe bearing housing cover 2 from the bearing housing 1 can be avoided orat least rendered more difficult.

The bearing housing cover 2 in this case is designed of aluminium, inparticular of die-cast aluminium or steel, wherein in the latter casethe bearing housing cover 2 can additionally have a corrosion protectionin the form of a nitrocarburizing or a burnishing. In order to be ableto manufacture the bearing housing cover 2 as cost-effectively aspossible yet of a high quality, it can be preferentially produced bymeans of a forming method, in particular by means of forging or coldextruding.

For sealing the bearing housing cover 2 against the bearing housing 1, aseal 5 can be additionally provided, which for example can be sprayedonto an end face of the bearing housing cover 2 by means of a screenprinting method. Additionally or alternatively, such a seal 5 canobviously be attached or sprayed on also in a corresponding location ofthe bearing housing 1. Obviously, the use of conventional O-ring sealsis also conceivable.

In order to be able to easily screw the bearing housing cover 2 into thebearing housing 1, the bearing housing cover 2 can comprise a drivingprofile 6, for example a Torx or an Allen (see in particular FIG. 2).

With the screwable bearing housing cover 2 according to the invention,the parts variety in particular can be reduced, since for exampleseparate fastening elements such as for example screws can be omitted.At the same time, the assembly of the bearing housing cover 2 to thebearing housing 1 is simplified. The screwing on/screwing in of thebearing housing cover 2 on/into the bearing housing 1 can be carried outby means of a suitable turning tool such as for example a socket or aTorx wrench, with which the bearing housing cover 2 is screwed into thebearing housing 1 against an axial bearing, to which for example theseal 5 is also attached. In order to be able to simplify the screwing-inof the bearing housing cover 2, the bearing housing cover 2 can becoated with a suitable sliding agent in particular in the region of itsfirst thread 3 and/or the bearing housing 1 in the region of its secondthread 4. Because of this, not only the assembly process, i.e. forexample the screwing-in can be simplified but in addition to this,thread damages during the screwing together, additionally avoided.

With the bearing housing cover 2 according to the invention and theassociated bearing housing 1 its assembly on the bearing housing 1 canthus be simplified and in addition the parts variety reduced, as aresult of which in particular storage and logistic costs can be reduced.

1. A bearing housing of a charging device, comprising: a bearing housingcover formed of metal, a first thread arranged on the bearing housingcover, a second thread arranged on the bearing housing and designedcomplementarily to the first thread so that the bearing housing covercan be screwed on and fixed on the bearing housing through a rotationalmovement.
 2. The bearing housing according to claim 1, wherein the firstthread is an external thread and the second thread is an internal threadcomplementarily formed thereto.
 3. The bearing housing according toclaim 1, wherein at least the first thread is of a self-locking design.4. The bearing housing according to claim 1, wherein the bearing housingcover is formed of aluminium.
 5. The bearing housing according to claim1, wherein the bearing housing cover has a driving profile.
 6. Thebearing housing according to claim 1, wherein the bearing housing coveris formed of steel and has a corrosion protection in the form of atleast one of a nitrocarburizing and a burnishing.
 7. The bearing housingaccording to claim 1, wherein the bearing housing cover is produced byat least one of forging and cold extruding.
 8. The bearing housingaccording to claim 1, wherein the bearing housing cover comprises aseal.
 9. (canceled)
 10. An exhaust gas turbocharger, comprising: abearing housing having a bearing housing cover formed of metal, a firstthread arranged on the bearing housing cover, and a second threadarranged on the bearing housing and designed complementarily to thefirst thread so that the bearing housing cover can be screwed on andfixed on the bearing housing through a rotational movement.
 11. Theturbocharger according to claim 10, wherein the first thread is anexternal thread and the second thread is an internal threadcomplementarily formed thereto.
 12. The turbocharger according to claim10, wherein at least the first thread is of a self-locking design. 13.The turbocharger according to claim 10, wherein the bearing housingcover is formed of aluminium.
 14. The turbocharger according to claim10, wherein the bearing housing cover has a driving profile.
 15. Theturbocharger according to claim 10, wherein the bearing housing cover isformed of steel and has a corrosion protection in the form of at leastone of a nitrocarburizing and a burnishing.
 16. The turbochargeraccording to claim 10, wherein the bearing housing cover is produced byat least one of forging and cold extruding.
 17. The turbochargeraccording to claim 10, wherein the bearing housing cover comprises aseal.
 18. The bearing housing according to claim 8, wherein the bearinghousing cover comprises a seal moulded on by a screen printing method.19. The bearing housing according to claim 4, wherein the bearinghousing cover is formed of at least one of die-cast aluminium and steel.20. The bearing housing according to claim 5, wherein the drivingprofile is at least one of a Torx and an Allen.